The machining of semi-finished workpiece edges in individual manufacturing steps is used in large semi-finished products such as cast parts, or in the small-batch production of in particular metal components in order to reduce the risk of an operator becoming injured and to prepare additional process steps. Here, the existing edge geometry is machined by the operator manually guiding the workpiece on the machining tool. This removes any burrs, for example deburring cast pieces, a defined chamfer can be produced, for example chamfering aluminium or plastics workpieces that have already been machined, or the edge can be given a complex geometry using the tool, for example by contour milling or beveling visible elements such as glass, mirrors or wood veneering. These machining options are conventionally carried out on table-top apparatuses or freestanding apparatuses, a machining tool element which projects beyond the machining table, rotates about its own axis and has geometrically defined cutting edge or cutting edges usually being used. A guiding element may in this case engage over the machining tool, projecting in an L-shape from the machining table, and may end in a rounded stop face, tangentially to the rotational axis thereof. A workpiece is guided along the workpiece geometry to be machined such that the guiding element is in position on the workpiece edge to be machined. Table-top or freestanding apparatuses having a machining table that is axially and angularly adjustable relative to the machining plane are used to set the cutting depth and the cutting angle, the machining tools used for workpiece machining being detachably connected to a drive unit only in a highly complex manner.
Here, the fact that the workpieces are taken to the machining table and are manually placed on the guiding element of the tool and/or on the work table using muscle power is usually characteristic of the machining process. In order to carry out machining, the workpiece is moved along on the guiding element by the operator. Depending on the axial setting of the machining table, the cutting tool element rotating thereunder removes material from an edge of the workpiece and thus produces the desired edge geometry. Chips that are produced either remain in the available space between the workpiece and the machining table or are sucked away.
For edges that are present on the workpiece, for example for recesses or grooves, the overarching guiding element however usually presents a limitation to the machining options owing to the size of said element and the connection to the machining table, which lies outside the tool. Particularly narrow grooves, shallow recesses, edges having short radii and acute angles, thus particularly complex geometries, often cannot be produced thereby, or can only be produced with difficulty. This may be due to the fact that the L-shaped guiding element is too high for shallow recesses and too wide for narrow grooves. In addition, machining whilst simultaneously monitoring the work result in internal machining operations that are covered by the workpiece is only possible with difficulty. In this case, the machining may be carried out without direct visual monitoring and is usually specified solely on the basis of the operator's experience. In this case, for example if there are sudden changes in direction, the back of the guiding element may come into contact with the edge to be machined and may thereby give the impression that the machining tool itself is in contact and machining is taking place. This potentially incorrect assumption and the resulting unsatisfactory machining of a workpiece is usually only eliminated by a subsequent check and by lifting up the workpiece, as is associated with said check, and this may possibly require extra work if the quality is inadequate.
Another field of application of manually handling and smoothing machined edges produced in a material-removing or sheared manner is that of repair processes for aluminium or fibre-composite shell elements in aviation. Here, damaged and non-removable structural components such as the outer skin of aircraft are manually cut out and reinforced by metal sheets or structures that are additionally attached. In order to prevent crack formation starting from the cut edges on the machined edge, the edges are smoothed. The resulting cut edges, in particular in aluminium, are deburred and smoothed using simple scraping or geometrically undefined abrasive tools, owing to the shape of the repair site and the fact that it is often difficult to access. Here, the operator draws a dragging blade along the workpiece edge, or alternatively the machining is carried out using abrasive material. In both cases, defined geometric machining of the edges is usually not possible. Furthermore, finishing work is particularly important for fibre-composite components owing to the high strength and hardness of the fibre elements. The high-strength fibres may, for example, be torn from the matrix during machining, these defects representing the start of cracks. Likewise, chips may be pressed between the individual fibre layers, and this may therefore form a starting point for delamination and possible failure of the component. It is particularly necessary to smooth these cut edges.
The publication of the German patent application DE 10 2007 060 215 A1 describes a device for machining a running edge.